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    <div class="refentry"><a id="equals"></a><div class="titlepage"></div><a id="IndexEqualsColon" class="indexterm"></a><a id="IndexEqualsQuestion" class="indexterm"></a><a id="IndexEqualsExpression" class="indexterm"></a><a id="IndexEquals" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">==</span></h2><p>== — 
      Compares two values for equality.
                            </p></div><div class="refsect1"><a id="idp88508960"></a><h2>Description</h2><p>
      Compares two values for equality.
    </p></div><div class="refsect1"><a id="idp88510288"></a><h2>Syntax</h2><pre class="synopsis">(a <span class="command"><strong>==</strong></span> b <span class="command"><strong>?</strong></span> v1 <span class="command"><strong>:</strong></span> v2)</pre><p>
      where <span class="emphasis"><em>a</em></span>, <span class="emphasis"><em>b</em></span>, <span class="emphasis"><em>v1</em></span> and <span class="emphasis"><em>v2</em></span> may be expressions, but <span class="emphasis"><em>a</em></span>, <span class="emphasis"><em>b</em></span> not audio-rate.
    </p></div><div class="refsect1"><a id="idp88516704"></a><h2>Performance</h2><p>
      In the above conditional, <span class="emphasis"><em>a</em></span> and <span class="emphasis"><em>b</em></span> are first compared. If the indicated relation is true (<span class="emphasis"><em>a</em></span> is equal to <span class="emphasis"><em>b</em></span>), then the conditional expression has the value of <span class="emphasis"><em>v1</em></span>; if the relation is false, the expression has the value of <span class="emphasis"><em>v2</em></span>. (For convenience, a sole "<span class="emphasis"><em>=</em></span>" will function as "<span class="emphasis"><em>= =</em></span>".)
    </p><p>
      NB.: If <span class="emphasis"><em>v1</em></span> or <span class="emphasis"><em>v2</em></span> are expressions, these will be evaluated before the conditional is determined.
    </p><p>
      In terms of binding strength, all conditional operators (i.e. the relational operators (<span class="emphasis"><em>&lt;</em></span>, etc.), and <span class="emphasis"><em>?</em></span>, and <span class="emphasis"><em>:</em></span> ) are weaker than the arithmetic and logical operators (<span class="emphasis"><em>+</em></span>, <span class="emphasis"><em>-</em></span>, <span class="emphasis"><em>*</em></span>, <span class="emphasis"><em>/</em></span>, <span class="emphasis"><em>&amp;&amp;</em></span> and <span class="emphasis"><em>||</em></span>).
    </p><p>
      These are <span class="emphasis"><em>operators</em></span> not <span class="emphasis"><em>opcodes</em></span>. Therefore, they can be used within orchestra statements, but do not form complete statements themselves.
    </p></div><div class="refsect1"><a id="idp88528720"></a><h2>Examples</h2><p>
      Here is an example of the == operator. It uses the file <a class="ulink" href="examples/equals.csd" target="_top"><em class="citetitle">equals.csd</em></a>.
      </p><div class="example"><a id="idp88530576"></a><p class="title"><strong>Example 32. Example of the == operator.</strong></p><div class="example-contents"><p>See the sections <a class="link" href="UsingRealTime.html" title="Real-Time Audio"><em class="citetitle">Real-time Audio</em></a> and <a class="link" href="CommandFlags.html" title="Csound command line"><em class="citetitle">Command Line Flags</em></a> for more information on using command line flags.</p><pre class="programlisting">
<span class="csdtag">&lt;CsoundSynthesizer&gt;</span>
<span class="csdtag">&lt;CsOptions&gt;</span>
<span class="comment">; Select audio/midi flags here according to platform</span>
-odac   <span class="comment">;;;realtime audio out</span>
<span class="comment">;-iadc    ;;;uncomment -iadc if realtime audio input is needed too</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o equals.wav -W ;;; for file output any platform</span>
<span class="csdtag">&lt;/CsOptions&gt;</span>
<span class="csdtag">&lt;CsInstruments&gt;</span>

<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">ksmps</span> <span class="op">=</span> 32
<span class="ohdr">nchnls</span> <span class="op">=</span> 2
<span class="ohdr">0dbfs</span>  <span class="op">=</span> 1
	
<span class="oblock">instr</span> 1

ienv <span class="op">=</span> p4				<span class="comment">;choose envelope in score</span>

<span class="octrl">if</span> (ienv <span class="op">==</span> 0) kthen 	
  kenv <span class="opc">adsr</span> 0.05, 0.05, 0.95, 0.05	<span class="comment">;sustained envelope</span>
<span class="octrl">elseif</span> (ienv <span class="op">==</span> 1) kthen 
  kenv <span class="opc">adsr</span> 0.5, 1, 0.5, 0.5		<span class="comment">;triangular envelope</span>
<span class="octrl">elseif</span> (ienv <span class="op">==</span> 2) kthen 
  kenv <span class="opc">adsr</span> 1, 1, 1, 0			<span class="comment">;ramp up</span>
<span class="octrl">endif</span>

aout   <span class="opc">vco2</span> .1, 110, 10
aout   <span class="op">=</span> aout <span class="op">*</span> kenv
       <span class="opc">outs</span> aout, aout

<span class="oblock">endin</span>

<span class="csdtag">&lt;/CsInstruments&gt;</span>
<span class="csdtag">&lt;CsScore&gt;</span>

<span class="stamnt">i</span>1 0 2  0
<span class="stamnt">i</span>1 3 2  1
<span class="stamnt">i</span>1 6 2  2

<span class="stamnt">e</span>
<span class="csdtag">&lt;/CsScore&gt;</span>
<span class="csdtag">&lt;/CsoundSynthesizer&gt;</span>
</pre></div></div><p><br class="example-break" />
    </p></div><div class="refsect1"><a id="idp88534864"></a><h2>See Also</h2><p>
      <a class="link" href="greaterequal.html" title="&gt;="><em class="citetitle">&gt;=</em></a>, 
      <a class="link" href="greaterthan.html" title="&gt;"><em class="citetitle">&gt;</em></a>, 
      <a class="link" href="lessequal.html" title="&lt;="><em class="citetitle">&lt;=</em></a>, 
      <a class="link" href="lessthan.html" title="&lt;"><em class="citetitle">&lt;</em></a>, 
      <a class="link" href="notequal.html" title="!="><em class="citetitle">!=</em></a>
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